Marjorie Harris' tips for creating a gorgeous, thriving garden

Designers design gardens, but almost anyone can get the sophistication of a well-designed garden into a backyard by following some very basic principles of garden design.

First, don't buy plants indiscriminately. One of everything will end up in a visual moosh. Save your money until you know what you need.

Don't bother with vegetables unless you've got sun for 6 hours a day, and you are willing to water and weed on a daily basis.

Do figure out how many hours a week you will spend in the garden; even with a low maintenance garden, there's work to be done. Plan according to your time and budget.

Second, evaluate what you've got. Which way does your garden face? Calculate where you have sun spots for 4 to 6 hours a day and apply this information to plant research. Examine all the contours of the garden and enhance any humps by building a berm — piling up soil and covering it with compost.

Third, divide the garden into logical sections or 'rooms'. Go at them one at a time, but have an overall vision of what the garden should look like from specific parts of the house. I chose a chair at my dining room table and when things look good from this angle, I know I'm doing the right thing.

With the preliminary planning done, it's time to choose your trees, shrubs and plants, and lay them out for maximum visual impact.

Every garden needs a focal point. It can be a structure (a gazebo, a patio) or a spectacular plant. The cheapest option is a stupendously gorgeous tree or shrub that gives really good value all year round. Examine the bark: does it exfoliate? Have wonderful stripes? Understand the volume of the plant at maturity: just how wide will it get? Read tags and take them seriously. Even dwarf plants defy logic — they can be 10 centimetres or 6 meters tall and wide. All shrubs are three-dimensional, very much like sculptures, so think of them as having the same aesthetic value.

Big structural trees come in every shape, size and colour — they are the most thrilling creatures to plant — never be casual about them. Trees are crucial for screening, privacy, beauty, as well as creating a vertical element. I planted a Kentucky Coffee Tree (Gymnocladus dioicus) for a strong central focus to both front and back gardens. It's native to my area, a factor that should be taken into consideration anywhere in the country. Since this is going to be a big ticket item, make sure you know what climate zone you live in (check planthardiness.gc.ca).  

The most graceful garden presents itself in layers. Once you know what trees will grow well, look for large shrubs or small trees as the next level down (2 to 3 metres). We often forget this important aspect of design: eye level. You should have the feeling of walking through plants.

Employ a mix of both evergreen and deciduous trees and shrubs throughout. We need the evergreens for winter interest, as well as for bird and animal habitats. If you want to attract butterflies for instance, get Buddleia, Eupatorium and your local milkweed. Outline where you will plant using bamboo stakes or hoses. Move plants around until a pattern emerges: colour; contrasting textures; harmonious skeletal shapes.  

The last plants to buy are perennials and annuals to add colour to the garden. Buy plants with similar hues in the bloom to get a drift of colour. Tuck in the tall ones front as well as back of the border — use them to create an undulating effect with medium-sized perennials as a contrast. Last of all, add edgers along walkways to soften stonework, plus use lots of ground covers such as hellebores. This autumn, pop in hundreds of small naturalizing bulbs. They will provide the soil with cover and feed early spring insects. The amazing colours are a bonus. This way you will have something coming up and earning its place in every season.

Finally, prep your soil. Unless you have fantastic soil, amend your soil — not necessarily with triple mix. A good black soil is the safest thing to use. Lay a couple of inches of compost at soil level and dress with mulch when you've finished planting. From now on the soil should not be disturbed. The first year this garden must be watered deeply twice a week: a sprinkler running for 45 minutes in each area it reaches; or each big plant watered to the count of 100, down to 30 for perennials. This type of garden, designed with such a rich biodiversity, will eventually survive with what nature offers to thrive and be absolutely gorgeous for decades.

Marjorie Harris has been gardening for the past 40 years in her own backyard; written 15 books about Canadian gardening including Botanica: North America: An Illustrated Guide to Our Native Plants, and most recently Thrifty Gardening From The Ground Up. She is a garden and plant consultant, garden writer and columnist for the Globe and Mail. She lives and makes gardens in Toronto. See: www.marjorieharris.com and marjorieharrisgardens.ca. Follow her on Twitter: @Marjorie_harris.